Characterization of a plant-produced recombinant human secretory IgA with broad neutralizing activity against HIV

Matthew Paul, Rajko Reljic, Katja Klein, Pascal M.W. Drake, Craig Van Dolleweerd, Martin Pabst, Markus Windwarder, Elsa Arcalis, Eva Stoger, More Authors

Research output: Contribution to journalArticleScientificpeer-review

33 Citations (Scopus)


Recombinant Secretory IgA (SIgA) complexes have the potential to improve antibody-based passive immunotherapeutic approaches to combat many mucosal pathogens. In this report, we describe the expression, purification and characterization of a human SIgA format of the broadly neutralizing anti-HIV monoclonal antibody (mAb) 2G12, using both transgenic tobacco plants and transient expression in Nicotiana benthamiana as expression hosts (P2G12 SIgA). The resulting heterodecameric complexes accumulated in intracellular compartments in leaf tissue, including the vacuole. SIgA complexes could not be detected in the apoplast. Maximum yields of antibody were 15.2 μg/g leaf fresh mass (LFM) in transgenic tobacco and 25 μg/g LFM after transient expression, and assembly of SIgA complexes was superior in transgenic tobacco. Protein L purified antibody specifically bound HIV gp140 and neutralised tier 2 and tier 3 HIV isolates. Glycoanalysis revealed predominantly high mannose structures present on most N-glycosylation sites, with limited evidence for complex glycosylation or processing to paucimannosidic forms. Oglycan structures were not identified. Functionally, P2G12 SIgA, but not IgG, effectively aggregated HIV virions. Binding of P2G12 SIgA was observed to CD209 / DC-SIGN, but not to CD89 / FcalphaR on a monocyte cell line. Furthermore, P2G12 SIgA demonstrated enhanced stability in mucosal secretions in comparison to P2G12 IgG mAb.

Original languageEnglish
Pages (from-to)1585-1597
Issue number6
Publication statusPublished - 2014
Externally publishedYes


  • Antibody stability
  • Glycosylation
  • HIV microbicide
  • Molecular farming
  • Secretory IgA


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